NextVideoConverterExpress provides an easy way to convert most popular video formats to MP4, MOV, AVI, WMV, and FLV on Mac OS X. It also enables users to convert videos for iPad, iPhone, iPod, and Apple TV with high quality. It can convert multiple video and audio files in batches.
This tool can help you trim video/audio to get video/audio clips and just convert a certain part of the source file. In addition, it allows you to merge all files into one file after convertion.